1. Field of the Invention
The present invention relates to a method and apparatus for rejacketing of stripped carriers of electromagnetic energy and the product obtained thereby and, in particular, to rejacketing of optical fibers, such as glass and plastic-based fibers.
While the present invention is applicable, in general, to rejacketing of carriers of electromagnetic energy, it was specifically developed and directed to optical fibers. However, for purposes of describing the present invention, discussion will be directed specifically to optical fibers. Nonetheless, it is to be understood that the present invention is not to be limited thereto but, in general, to other forms of carriers of electromagnetic energy.
2. Description of Related Art and Other Considerations
Splicing of optical fibers requires that protective insulative jackets be stripped from each optical fiber to permit their exposed ends to be spliced together. Thereafter, the spliced fibers must again be rejacketed. Prior techniques and the resulting products, while generally competent to provide an effective rejacketing, have problems. Most employ curing of light sensitive jacketing material by photo curing, e.g., by ultra-violet and blue light.
Conventional rejacketing methods may be divided into two categories, viz., one not needing a mold and one that uses a mold, either rigid or soft. The non-mold techniques utilize some form of mechanical connector, such as a heat-produced shrink fitting, which is large in size and bulky. The new jacket is also bulky. However, it is fast and rugged. The mold-using methods are difficult to assemble and are hard to automate. Further, some hard molds have holes which become clogged with cured jacketing material and which, therefore, need to be periodically cleaned. Soft molds wear out faster than hard molds and, therefore, need frequent replacement. However, their advantage over hard molds is that they are easier to clean. Known methods are discussed as follows.
In the "Silicone Mold" method, while the molds do not damage the fiber and fairly consistent rejacketing results, the molds need to be replaced often, the method presents difficulties in being automated, and bubbles need to be removed.
The "Vytran Glass Die" method produces very consistent rejacketing and is not subject to wear; however, it is imperative that the spliced fibers and associated jackets be clean and the use of epoxy provides loading difficulties.
It is easy to set up the "Dip and Cure" method, which does not require a mold. However, the cure must be quick to minimize beading of epoxy on the fiber and the new jacket may not be uniform. Further, this process requires the ability to automatically dip the fiber into the epoxy.
The "Brush and Cure" method is very easy to set up and requires no mold. However, the cure needs to be quick to minimize beading of epoxy on the fiber, the jacket is not uniform, and the fiber must be contacted with a brush.
The "Pull Through a Drop/cure" process is also easy to set up and does not require a mold or, furthermore, any contact with the fiber. Its deficiencies include the need for a quick cure to minimize beading of epoxy on the fiber and the new jacket is not uniform.
In the "Spray" method, no mold is required and the fiber is not subject to contact. Like some of the other processes, the cure needs to be quick to minimize beading of epoxy on the fiber, the rejacketing is not uniform, and good environmental containment is needed.
In moldless processes, beading often is produced. When used, molds add cost and complexity.